1. Field of the Invention
The present invention relates to a device for performing at least two operations on one or more workpieces in a single stroke of a press ram. More particularly, the present invention relates to a pressing and staking device that first presses two workpieces together and thereafter stakes one of the workpieces to secure the two together. The present invention also relates to a method for applying, in a single stroke of a press ram, pressure to one workpiece to, for example, fit it to a second workpiece, and thereafter applying a different pressure to one of the workpieces to, for example, stake it and secure the two together.
2. Description of the Prior Art
Pressing and staking devices are known. For example, U.S. Pat. No. 3,111,867 (Riggio) discloses a double-acting staking apparatus that comprises a first piston for supporting an assembly of workpieces and for moving the workpieces upwardly toward a punch holder. A staking punch is slidable in the holder and operated by a second piston. In operation, the first piston moves the assembly of workpieces upwardly toward the punch holder to apply a predetermined pressure to the assembly. Then, the staking punch is moved downwardly in a direction opposite the direction of the first piston, to stake one of the workpieces to complete the assembly.
U.S. Pat. No. 4,035,901 (Lux et al) discloses an apparatus for joining two abutting metal members and has a single reciprocating head comprising a section that performs a lancing and forming operation on a first stroke of the head and a second section that performs a staking operation on a second stroke of the head.
A press for assembling a fastener to a workpiece is disclosed in U.S. Pat. No. 3,465,410 (Ernest et al.).